Devices for applying viscous substances to paper, cardboard, and other surfaces are known in the art. An early illustration of one structure used to accomplish this function in U.S. Pat. No. 346,870 issued to I. Sherck et al on Aug. 3, 1886. The device of that patent was used for effecting the coating of paper and other material with a wax lamina. Its structure included a cylinder which was mounted on a hollow shaft. The cylinder was made to rotate with the shaft so that melted paraffin or other wax fed into the shaft would be centrifugally displaced through perforations in the shaft and would pass outwardly to the surface of the cylinder drum. The cylinder drum was also perforated so that the paraffin could ooze through these perforations and be applied by the drum to the paper desired to be coated.
A more recent illustration of a similar device is U.S. Pat. No. 3,408,984 (Pullins) issued on Nov. 5, 1968. The structure of that reference also utilized a drum mounted for rotation with a hollow shaft. Adhesive introduced into the shaft was allowed to exit through openings in the shaft into the inside of the drum. The drum included a multiplicity of perforations formed in the surface thereof. A porous or liquid permeable applicator was positioned on the drum at a location so that the applicator could receive adhesive oozing through perforations in the drum and apply that adhesive to a desired surface. Perforations which were not covered by the porous or liquid permeable applicator were plugged so that adhesive would not flow through those pores.
In the case of both of these structures, the radially outward flow of the substance to be deposited was occasioned by the centrifugal force imparted thereto as the result of rotation of the shaft and cylinder. One specific problem, however, with both structures is that there is no means for insuring equal distribution of the substance around the peripheral interior of the drum. With the Sherck reference, there is not even any means for insuring the location about the periphery of the drum at which the substance would be dispensed. Additionally, in view of the highly viscous nature of the substances with which the structures of those two references are to be used, those references don't teach any method for keeping the substance relatively fluid during the application process. Those structures are deficient also in that they are designed for application of the dispensed substance to a surface having a fixed dimension. Little flexibility was incorporated to adjust the area of dispensing should application of the substance to a smaller surface be necessary.
It is these deficiencies in the art which the invention of the present application is directed. The structure in accordance with this invention is an improved apparatus for centrifugally dispensing a viscous substance with uniform distribution at the area of dispensing.